People seek after signs and wonders because they don't take God at His word as Abraham did! They do not have the faith of Abraham or any faith for that matter. If we cannot believe in the revelation that God has given in the scriptures we are lost, and without hope in the world. Only as we accept and believe what God has spoken through all those who have penned the scriptures will we cease to seek after signs and wonders. In the last days the false prophet will be able to do great signs and wonders and the whole would will be deceived by that agent of Satan.
Mr 13:22 For false Christs and false prophets shall rise, and shall shew signs and wonders, to seduce, if it were possible, even the elect.
Re 19:20 and the beast was taken, and with him the false prophet who did the signs before him, in which he led astray those who did receive the mark of the beast, and those who did bow before his image; living they were cast — the two — to the lake of the fire, that is burning with brimstone;

This is a bit more complex than what I see written here, so I will open the proverbial can of worms. The backspace signs and wonders Jesus performed were primarily in the form of miraculous healings. Therefore, I would add to this list that many seek signs or wonders in the form of miraculous healings, and their primary reason for doing so is quite simple. They are desperate for one. Parents with a child suffering from leukemia, astrocytoma or some other severe malady, and adults diagnosed with chronic, debilitating or terminal illnesses are the best examples. So many of these people – Christians and non-Christians alike – are desperate for a cure, which modern medicine cannot provide them with.
It is, in some ways, a quest for a present-day fulfillment of the Gospels, where we read that Jesus healed everyone who came or was brought to Him (Matt 4:24, 8:16; Acts 10:38). Even in giving the great commission, our Lord told his disciples they were to heal the sick and raise the dead, as well as cast out demons from the oppressed (Matt10:1, 7-8; Mark 3:13-19; Luke 6:12-16). (The Acts of the Apostles a.k.a. [The book of Acts] is a compilation of such examples.) Since Scripture says that Jesus is the same yesterday, today, and forever, and He said He would be with us until the end of the age, many Christians are inclined to believe these words are intended for today, and not solely as first and second century signs and wonders necessary for the establishment of the church, they are drawn to those who claim to or are said by others to perform miracles in this present hour.
Unfortunately, so many of these so-called "healers" have been repeatedly exposed as charlatans, false prophets, adulterers, heretics, etc. There programming so saturates Christian networks, and their claims and testimonials are presented in such an atmosphere of excitement, that it is difficult for those seeking answers for impossible situations, not to be drawn to them. I believe this is because human nature has at its base a dichotomy. On the one hand, it will cling to hope up to the very last moment, or on the other, it will embrace pessimism. Since pessimism leads to hopelessness and depression, and biblical faith is built on hope (Heb 11:1), depression is obviously neither a logical or biblical. Yet, it is an inextricable portion of the mix.
Dr. Elizabeth Kubler Ross wrote in her now famous tome, On Death and Dying, there are natural stages within the human psyche each individual experiences when facing death or devastating loss. Before any individual can truly accept the prospect of death, they will embrace denial. (This isn't necessarily evil, simply the way we are wired.) However, Ross's studies show that one must overcome denial and embrace acceptance of their situation in order to progress in a healthy manner, for it is only in this stage that one can say "it's going to be okay," or "I can't fight it, I may as well prepare for it." The problem is one must navigate human tendencies to negotiate with God for a better outcome (Bargaining Stage) or becomes so introspective and self absorbed to embrace defeatism and say "I'm going to die soon so what's the point?" or "I miss my loved one so much, I simply can't go on living." (Depression Stage). The longer we stay in bargaining or depression, the more unhealthy it is for us and our families.
Seeking out those with the gift of healing certainly has scriptural foundation (I Cor 12:9, 28, Eph 4:11), depending on where one stands regarding Pentecost. However, the biggest problem with it is that it has created a conduit for wolves in sheep's clothing (Matt 7:15; Rom 14:1-12) to carry on charades in the name of Jesus Christ, that are borderline carnivals. Spouting profound declarations and promises in the name of God, they prey upon the desperate and needy in the church, all the time making themselves more and more wealthy. They account to no one, except, perhaps, those who bankrolled their traveling roadshows.

The reason why people seek for signs and wonders is because they are not aware of the purpose of signs.
Miracles were performed by God for two reasons: firstly that people may acknowledge the creator, whose name is "Jealous" (Exodus :34:14) and secondly that they may "serve" him. The way to serve him is through a life of obedience.
God performed miracles in Egypt for one reason: that his lost children may acknowledge him and serve him only. The nation of Israel had seen and experienced all the miracles but refused to serve him.
God was silent for four hundred years because of Israel's disobedience, a nation who received and experienced miracles but refused to "serve".
The Christ was sent to raise up a body to serve the God of the Bible. Like Jehovah in the old testament, Jesus also performed miracles to point people to God; the reason was to acknowledge God and serve him.
The people in the church are ones who have acknowledge the creator. Their ultimate purpose is to "serve" him, not to look for signs and wonders. They have no need to seek for miracles or signs because they have the greatest miracle in them.
Signs and wonders are not for the church, because they "believe". It is good for ones that are moving with this gift of signs and wonders to go to the mosque or an heathen temple and perform these signs and point them to the living God.
In the book of Acts, the apostle Peter performed a miracle at the Jewish temple, which caused a "stir". These were the same Jews who crucified the Christ.

Miracles and signs are good things. You may request them for yourself in humility. I like to pray to know whether I should ask, even before I ask for the actual sign (usually, I ask to confirm or deconfirm something). In this way, I also get to know the holy spirit, better.
Jesus maybe never needed a sign. That's my assumption. He would know the spirit and the Father perfectly. We cannot make that claim. In a way, pretending you can operate on blind faith your whole life seems like hubris. I doubt it can be done.
So, as in Isaiah 7:9-13, I think we are often expected, and even commanded, to ask for the signs we need to "stand firm."